In the processing of metal bearing ores, such as tungsten ores, waste sludges are generated. These sludges can present disposal problems because such sludges do not degenerate and contain sufficient metal values to make normal waste treatment via normal sewage treatment impractical.
U.S. Pat. No. 4,624,703 issued Nov. 25, 1986 and assigned to GTE Products Corporation, discloses a process for recovering tungsten, scandium, iron and manganese from a tungsten bearing material via a solvent extraction process using a dialkyl phosphoric acid to extract the scandium. U.S. Pat. No. 4,624,703 and the disclosure thereof is incorporated by reference herein.
U.S. Pat. No. 4,626,280 issued Dec. 2, 1986 and assigned to GTE Products Corporation discloses another process for recovering tungsten, scandium, iron and manganese from a tungsten bearing material via a process in which the material is digested in an aqueous sulfur dioxide solution and a tertiary alkyl primary amine is used as an extracting agent for the scandium. U.S. Pat. No. 4,626,280 and the disclosure thereof is incorporated by reference herein.
U.S. Pat. No. 4,718,995 issued Jan. 12, 1988 and is assigned to GTE Products Corporation is a continuation-in-part of the aforementioned U.S. Pat. No. 4,626,280 and discloses using sulfuric acid and a reducing agent to digest the tungsten bearing material. U.S. Pat. 4,718,995 and the disclosure thereof is incorporated by reference herein.
U.S. Pat. No. 4,718,996 issued Jan. 12, 1988 assigned to GTE Products Corporation is a continuation-in-part of U.S. Pat. No. 4,624,703, mentioned above. U.S. Pat. No. 4,718,996 discloses the additional aspect of using a sulfur dioxide aqueous solution to digest the tungsten bearing material. U.S. Pat. No. 4,718,996 and the disclosure thereof is incorporated by reference herein.
U.S. Pat. No. 4,808,384 issued Feb. 28, 1989 assigned to GTE Products Corporation relates to the process disclosed in U.S. Pat. No. 4,624,703 mentioned above. U.S. Pat. No. 4,808,384 discloses the additional aspect of using coal as a reducing agent in the digestion step. That patent and the disclosure thereof is incorporated by reference herein.
A process that turns such wastes into usable products cost-effectively is believed to be an advancement in the art.